stm32_template/module_Template/MLX90614红外测温/MLX90614.c

#include "MLX90614.h"


#define ACK         0
#define NACK        1
#define SA                        0x00 
#define RAM_ACCESS                0x00 
#define EEPROM_ACCESS             0x20 
#define RAM_TOBJ1                 0x07 

#define SMBUS_PORT               GPIOB
#define SMBUS_SCK                GPIO_Pin_7
#define SMBUS_SDA                GPIO_Pin_6

#define RCC_APB2Periph_SMBUS_PORT                RCC_APB2Periph_GPIOB

#define SMBUS_SCK_H()            SMBUS_PORT->BSRR = SMBUS_SCK
#define SMBUS_SCK_L()            SMBUS_PORT->BRR = SMBUS_SCK
#define SMBUS_SDA_H()            SMBUS_PORT->BSRR = SMBUS_SDA
#define SMBUS_SDA_L()            SMBUS_PORT->BRR = SMBUS_SDA

#define SMBUS_SDA_PIN()            SMBUS_PORT->IDR & SMBUS_SDA 

void SMBus_StartBit(void)
{
    SMBUS_SDA_H();                // Set SDA line
    SMBus_Delay(8);            // Wait a few microseconds
    SMBUS_SCK_H();                // Set SCL line
    SMBus_Delay(8);            // Generate bus free time between Stop
    SMBUS_SDA_L();                // Clear SDA line
    SMBus_Delay(8);            // Hold time after (Repeated) Start
    // Condition. After this period, the first clock is generated.
    //(Thd:sta=4.0us min)
    SMBUS_SCK_L();            // Clear SCL line
    SMBus_Delay(8);            // Wait a few microseconds
}

void SMBus_StopBit(void)
{
    SMBUS_SCK_L();                // Clear SCL line
    SMBus_Delay(8);            // Wait a few microseconds
    SMBUS_SDA_L();                // Clear SDA line
    SMBus_Delay(8);            // Wait a few microseconds
    SMBUS_SCK_H();                // Set SCL line
    SMBus_Delay(8);            // Stop condition setup time(Tsu:sto=4.0us min)
    SMBUS_SDA_H();                // Set SDA line
}

u8 SMBus_SendByte(u8 Tx_buffer)
{
    u8        Bit_counter;
    u8        Ack_bit;
    u8        bit_out;

    for(Bit_counter=8; Bit_counter; Bit_counter--)
    {
        if (Tx_buffer&0x80)
        {
            bit_out=1;   // If the current bit of Tx_buffer is 1 set bit_out
        }
        else
        {
            bit_out=0;  // else clear bit_out
        }
        SMBus_SendBit(bit_out);                // Send the current bit on SDA
        Tx_buffer<<=1;                                // Get next bit for checking
    }

    Ack_bit=SMBus_ReceiveBit();                // Get acknowledgment bit
    return        Ack_bit;
}

void SMBus_SendBit(u8 bit_out)
{
    if(bit_out==0)
    {
        SMBUS_SDA_L();
    }
    else
    {
        SMBUS_SDA_H();
    }
    SMBus_Delay(6);                                        // Tsu:dat = 250ns minimum
    SMBUS_SCK_H();                                        // Set SCL line
    SMBus_Delay(8);                                        // High Level of Clock Pulse
    SMBUS_SCK_L();                                        // Clear SCL line
    SMBus_Delay(8);                                        // Low Level of Clock Pulse
    return;
}

u8 SMBus_ReceiveBit(void)
{
    u8 Ack_bit;

    SMBUS_SDA_H();          
        SMBus_Delay(6);                        // High Level of Clock Pulse
    SMBUS_SCK_H();                        // Set SCL line
    SMBus_Delay(8);                        // High Level of Clock Pulse
    if (SMBUS_SDA_PIN())
    {
        Ack_bit=1;
    }
    else
    {
        Ack_bit=0;
    }
    SMBUS_SCK_L();                        // Clear SCL line
    SMBus_Delay(8);                        // Low Level of Clock Pulse

    return        Ack_bit;
}

u8 SMBus_ReceiveByte(u8 ack_nack)
{
    u8         RX_buffer;
    u8        Bit_Counter;

    for(Bit_Counter=8; Bit_Counter; Bit_Counter--)
    {
        if(SMBus_ReceiveBit())                        // Get a bit from the SDA line
        {
            RX_buffer <<= 1;                        // If the bit is HIGH save 1  in RX_buffer
            RX_buffer |=0x01;
        }
        else
        {
            RX_buffer <<= 1;                        // If the bit is LOW save 0 in RX_buffer
            RX_buffer &=0xfe;
        }
    }
    SMBus_SendBit(ack_nack);                        // Sends acknowledgment bit
    return RX_buffer;
}

void SMBus_Delay(u16 time)
{
    u16 i, j;
    for (i=0; i<5; i++)
    {
        for (j=0; j<time; j++);
    }
}

void SMBus_Init()
{
    GPIO_InitTypeDef    GPIO_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SMBUS_PORT, ENABLE);

    GPIO_InitStructure.GPIO_Pin = SMBUS_SCK | SMBUS_SDA;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(SMBUS_PORT, &GPIO_InitStructure);

    SMBUS_SCK_H();
    SMBUS_SDA_H();
}

u16 SMBus_ReadMemory(u8 slaveAddress, u8 command)
{
    u16 data;                        // Data storage (DataH:DataL)
    u8 Pec;                                // PEC byte storage
    u8 DataL=0;                        // Low data byte storage
    u8 DataH=0;                        // High data byte storage
    u8 arr[6];                        // Buffer for the sent bytes
    u8 PecReg;                        // Calculated PEC byte storage
    u8 ErrorCounter;        // Defines the number of the attempts for communication with MLX90614

    ErrorCounter=0x00;                                // Initialising of ErrorCounter
        slaveAddress <<= 1;        //2-7???????
        
    do
    {
repeat:
        SMBus_StopBit();                            //If slave send NACK stop comunication
        --ErrorCounter;                                    //Pre-decrement ErrorCounter
        if(!ErrorCounter)                             //ErrorCounter=0?
        {
            break;                                            //Yes,go out from do-while{}
        }

        SMBus_StartBit();                                //Start condition
        if(SMBus_SendByte(slaveAddress))//Send SlaveAddress ???Wr=0????????
        {
            goto        repeat;                            //Repeat comunication again
        }
        if(SMBus_SendByte(command))            //Send command
        {
            goto        repeat;                            //Repeat comunication again
        }

        SMBus_StartBit();                                        //Repeated Start condition
        if(SMBus_SendByte(slaveAddress+1))        //Send SlaveAddress ???Rd=1????????
        {
            goto        repeat;                     //Repeat comunication again
        }

        DataL = SMBus_ReceiveByte(ACK);        //Read low data,master must send ACK
        DataH = SMBus_ReceiveByte(ACK); //Read high data,master must send ACK
        Pec = SMBus_ReceiveByte(NACK);        //Read PEC byte, master must send NACK
        SMBus_StopBit();                                //Stop condition

        arr[5] = slaveAddress;                //
        arr[4] = command;                        //
        arr[3] = slaveAddress+1;        //Load array arr
        arr[2] = DataL;                                //
        arr[1] = DataH;                                //
        arr[0] = 0;                                        //
        PecReg=PEC_Calculation(arr);//Calculate CRC
    }
    while(PecReg != Pec);                //If received and calculated CRC are equal go out from do-while{}

        data = (DataH<<8) | DataL;        //data=DataH:DataL
    return data;
}

u8 PEC_Calculation(u8 pec[])
{
    u8         crc[6];
    u8        BitPosition=47;
    u8        shift;
    u8        i;
    u8        j;
    u8        temp;

    do
    {
        /*Load pattern value 0x000000000107*/
        crc[5]=0;
        crc[4]=0;
        crc[3]=0;
        crc[2]=0;
        crc[1]=0x01;
        crc[0]=0x07;

        /*Set maximum bit position at 47 ( six bytes byte5...byte0,MSbit=47)*/
        BitPosition=47;

        /*Set shift position at 0*/
        shift=0;

        /*Find first "1" in the transmited message beginning from the MSByte byte5*/
        i=5;
        j=0;
        while((pec[i]&(0x80>>j))==0 && i>0)
        {
            BitPosition--;
            if(j<7)
            {
                j++;
            }
            else
            {
                j=0x00;
                i--;
            }
        }/*End of while */

        /*Get shift value for pattern value*/
        shift=BitPosition-8;

        /*Shift pattern value */
        while(shift)
        {
            for(i=5; i<0xFF; i--)
            {
                if((crc[i-1]&0x80) && (i>0))
                {
                    temp=1;
                }
                else
                {
                    temp=0;
                }
                crc[i]<<=1;
                crc[i]+=temp;
            }/*End of for*/
            shift--;
        }/*End of while*/

        /*Exclusive OR between pec and crc*/
        for(i=0; i<=5; i++)
        {
            pec[i] ^=crc[i];
        }/*End of for*/
    }
    while(BitPosition>8); /*End of do-while*/

    return pec[0];
}

float SMBus_ReadTemp(void)
{   
	return (SMBus_ReadMemory(SA, RAM_ACCESS|RAM_TOBJ1)*0.02-273.15);
}